Your baseline for social utility is assuming a given that people should be extorted. You're saying if people just learned to enjoy the extortion, then there would be more social utility than if they didn't enjoy the extortion. I can't argue with you there, since utility is directly tied to human enjoyment.
But your baseline is absurd. If we look only at the utilitarian argument, it becomes obvious that social utility is much higher without mass extortion, than it possibly could be with mass extortion, regardless of how many people choose to enjoy their extortion.